Direction signal switch



April 21, 1942. P. WEIEN DIRECTION SIGNAL SWITCH Filed Nov. 22, 1939 3 Sheets-Sheet 1 w sghaa I ii\ In 0 er a for.

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April 21, 1942. P. WElEN DIRECTION SIGNAL SWITCH 3 Sheets-Sheet 2 Filed NOV. 22, 1939 Irzuezzior; @w M J Qua, l-q fliiarneys April-21, 1942. P. WElEN DIRECTION SIGNAL swxwca Filed NOV. 22, 1939 3 Sheets-Sheet 3 H In N Patented Apr. 21, 1942 DIRECTION SIGNAL SWITCH Paul Weien, Marietta, Pa., assignor of one-half to Henry S. Rich, Marietta, Pa.

Application November 22, 1939, Serial No. 305,637

9 Claims.

This invention relates to electrical direction signal systems for automotive vehicles and more particularly to a switch for controlling the opening and closing of the various signal circuits of such a system.

My prior Patent No. 1,910,869, May 23, 1933, shows a switch which may not only be manually set for closing either right or left turn signal circuits, but the same also automatically closes the signal circuits for a right or left turn on steering the vehicle into a right or left turn, respectively. To this end, the switch comprises a pair of relatively movable members having contacts which are disengaged from each other in the neutral position of both members and engage each other to close right or left turn signal circuits on movement of either member from its neutral position in opposite directions, respectively. One member, hereafter called automatic member, is moved by the steering mechanism of the vehicle and assumes its neutral position when the vehicle moves in a straight direction, while the other member, hereafter called manual member, is manually movable from its neutral position in either direction and normally spring-urged into neutral position. However, the manual member is locked against rotation in either direction on having been turned from its neutral position in either direction through a preassigned distance, and the same is automatically released when the automatic member .is moved by the steering mechanism from its neutral position. Thus, while the circuits for a particular direction signal may be closed by manipulating the manual member into the corresponding operative position, these same circuits remain closed until the vehicle completes the signalled turn even though the manual member hasin the meantime been released and spring-returned to its neutral position. However, this is true only if the automatic member is moved by the steering mechanism from its neutral position in a direction commensurate with the manual setting of the switch. If the switch is manually set for a left turn signal, for instance, and the vehicle makes in reality a right turn, the left turn signal circuits will be opened the moment the vehicle starts to turn to the right and the right turn signal circuits will then be closed on movement of the automatic member from its neutral position relative to the manual member which has meanwhile been released and spring-returned to its neutral position. If the switch is not manually set for any signal and the vehicle turns in either direction, the corresponding signal circuits will be automatically closed by reason of the movement of the automatic member relative to the manual member in its neutral position.

It is the primary aim and object of the present invention to devise a switch which performs like my prior switch as far as the manual operation of the same is concerned but which does not perform automatically, 1. e., fails to close any signal circuits while the manual switch member is in its neutral position even though the automatic switch member is moved from its neutral position by the steering mechanism.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

In the drawings:

Fig. 1 is a perspective view of a dis-assembled switch which embodies the present invention.

Fig. 2 is an enlarged section through the assembled switch.

Fig. 3 is a section taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a plan View of the switch as viewed in the direction of the arrow 4 in Fig. 6, the switch housing being partly broken away for clearer illustration of the switch elements therem.

Fig. 5 is a section through the switch taken substantially on the line 5-5 of Fig. 2.

Figs. 6 to 8, inclusive, are sections similar to Fig. 5, showing certain switch elements in different positions of operation however.

Figs. 9 and 10 are sections taken substantially on the lines 99 and l0l0, respectively, of Fig. 2.

Referring to the drawings, and more particularly to Figs. 1 and 2, the reference numeral I2 designates a direction signal switch having a cylindrical housing M in which the various switch elements are located. The open ends of the housing 14, which is preferably made of Bakelite, are closed by cover plates l8 and 20 whose peripheries rest in annular recesses 22 of said housing. A plurality of tie bolts 24 secure the cover plates 18, 2|] to the housing I4. The tie bolts 24, of which there are four in the present instance, are straddled by the fork legs 26 of inwardly projecting lugs 28 of the housing I4 (Figs. 1 and Rotatable in the switch housing is a carrier 30 for two brush holders 32, said carrier consisting of two metal plates 34 and 36 between which the brush holders are mounted diametrically opposite each other by means of studs 38 which extend through said holders and plates and have their ends riveted against the latter as at 39, thereby also securing the plates in spaced relation to each other. the end plate 34 is a stub shaft 46. In the present instance, a reduced end 42 of the stub shaft is provided with flats in its otherwise cylindrical periphery which engage the walls of a square hole 44 in the end plate 34, and spaced portions of said reduced shaft end are crimped against said end plate 34 as at 43 (Fig. 3) to permanently secure the latter to a collar 48 1 which is integral with the stub shaft 40. The stub shaft 40 itself is journalled in a bearing sleeve 50 (Fig. 2) which is secured to the cover plate I8 of theswitch housing by means of a nut 52 which is received by the threaded portion s 54 'ofsaid bearing sleeve and retains an annular shoulder 56 of the latter in engagement with said cover plate IS. The collar 48 of the stub shaft 40 is retained in engagement with the adjacent end of the bearing sleeve 56 by an ad- :2.

justable collar 58 which engages the other end of said bearing sleeve. Mounted on the stub shaft 40 is a lever 63) through intermediation of which the brush carrier 36 is to be rotated in a manner more fully described hereinafter.

As best shown in Figs. 1 and 4, each brush Projecting from I holder 32 consists of two parts 62 which are of any suitable insulating material, such as Bakelite, and have aligned rectangular grooves 64 which together form a rectangular opening 66 in which a correspondingly shaped conductive sleeve 68 is guided for movement radially of the brush carrier 30. Slidable in each sleeve 68 and projecting beyond the open ends thereof are two brushes I2 and 14 (Figs. 3 and 5) which are normally urged apart by an interposed spring I6, whereby a shoulder I8 of the brush I2 is urged against a shoulder I9 of the sleeve 63, while the other brush I4 is urged into engagement with a circular conductive track 89 which is suitably secured to the inner wall of the switch housing I4 as by a rivet 82 and a terminal 64. Each conductive sleeve 68 is furthermore provided with two V-shaped notches 66a and 862) with which the correspondingly V-shaped apex 68 of a leaf spring 89 is adapted to register. The leaf spring 89 is received in a recess 96 in each brush holder 32 and is anchored at both ends in the manner best shown in Fig. 5.

Adapted to cooperate with the brushes I2 is' a circular conductor 92 which may be molded directly into an insulating disk 94 which is mounted on the reduced end 93 of a stub shaft 98, journalled coaxially of the previously described stub shaft 49 in a bearing member I66 which is suitably mounted on the cover plate 20 of the switch housing. Instead of molding the conductor into a molded disc 94 of Bakelite, for instance, the disc 94 may be of any suitable insulating material and have a peripheral recess I02 to receive the conductor 92 which is in the present instance in form of a circular flange on a plate I04 which rests against the front face I06 of said disc and has an opening through which the reduced shaft end 96 extends with such clearance as to avoid contact between the latter and said plate I64. The foremost portion of the reduced shaft end 96 has preferably four spaced flats I08 in its otherwise cylindrical periphery that engage the walls of a square hole III! in a metal washer H2 which is provided with a nose H4 that projects into an aperture H6 in the disc 94, thereby securing said disc to the stub shaft 98 for combined rotation with the latter. An insulating washer H8 is interposed between the washer H2 and the conductor plate I34 to prevent grounding of the conductor 92 by way of said washer H2 and the stub shaft 83. Angularly spaced portions of the reduced shaft end 96 are crimped at I20 against the washer II2 (see also Fig. 1), thereby retaining the disc 94 in permanent engagement with an annular shoulder I22 on the stub shaft 98. As best shown in Fig. 3, an annular shoulder I24 on the stub shaft 46 abuts an annular shoulder I26 on the reduced end of the other stub shaft 98, and projecting from the shoulder I24 is a reduced shaft'end I28 which is received in a bore I36 in the reduced shaft end 96, thus providing a further journal bearing for the axially aligned stub shafts 40 and 93.

Suitably mounted on the stub shaft 98 or secured to the disc 94 and abutting the latter is a metal disc I32 whose hub I34 may extend into close proximity to the bearing member I!!!) on the cover plate 26. This disc I32 has three equiangularly spaced, punched-out cams I36 which are generally V-shaped as shown in dotted lines in Fig. 3. Urged against the disc I32 by means 5 of a star spring I38 is a non-rotatable but axially movable lock disc I40 which has three equiangularly spaced depressions I42 that conform in shape to the cams I36 and are arranged concentric to the latter and formed by punching out portions of the disc I46 in the manner illustrated in Figs. 2 and 3. The lock disc I46 is held nonrotatable by at least two studs I43 (Figs. 2 and 5) which project from the cover plate 20 of the switch housing and slidably receive sleeve-like projections I45 of said lock disc. The end plate 36 of the brush carrier 36 is provided with six equi-angularly spaced, Ipunched-out cams I44 which conform in shape to the cams I36, while the lock disc I40 has six more equi-angularly spaced depressions I45 which conform in shape to the cams I44 and are arranged concentric to the latter and formed by punching out portions of said look disc. In the neutral positions of the brush carrier 36 and rotary conductor 92 as shown in Figs. 2, 3 and 5, the cams I44 on said brush carrier are 30 displaced from the depressions I46 in the lock disc I46 and hold the latter depressed against the force of the star spring I38, while the cams I36 on the disc I32 align, but do not register, with the inner depressions I42 in said lock disc as best shown in Figs. 2, 3 and 5. While the rotary conductor 92 remains in its neutral position (Figs. 2, 3 and 5), and upon turning the brush carrier 36 in either direction from its neutral position through a distance of 30 into either of two operative positions of which one is shown in Fig. 6, the cams I44 on the brush carrier will come into alignment with the depressions I46 in the lock disc I46 and the latter will thereupon be urged by the star spring I38 into the locking position shown in Fig. 4 when the cams I36 and I44 come into registry with the depressions I42 and I46, respectively, in the lock disc. The registering cams I44 and depressions I46 on the brush carrier and in the lock disc, respectively, yieldingly arrest said brush carrier' against rotation from either operative position. Hence, the brush carrier is yieldingly arrested in either operative position until the lock disc I40 is sufliciently depressed to clear its depressions I46 from the cams I44. Depression ofthe lock disc I40 to that extent is accomplished on turning the conductor 92 from its neutral position in either direction through intermediation of a lever I56 on the stub shaft .98 and in a manner to be described more fully hereinafter. Rotation of the disc I32 with the conductor from its neutral position causes the cams I36 to depress the lock disc I40 in order to clear the depressions I42 thereof, whereby the other depressions I46 in the lock disc also clear .the cams I44 on the-brush carrier and permit the return of the latter to its neutral position.

The brush carrier 38 is normally yieldingly urged intoits neutral position by means of two levers I58 and I60 (Figs. 1 and 9) which are pivotally mounted at. I62 and I64, respectively, on the cover plate, I8 of the switch housing. The straight ends I65 and I66 of the levers I58 and J60, respectively, are normally urged by a tension spring I10 into engagement with a post I68 on the cover plate I8. Projecting from the end plate 34 of the brush carrier is a stud I12 which is of .the same diameter as the post I68 and projects between the lever ends I65 and I66 (see also Fig. 2). When both lever ends I85 and I66 envehicle. These signal bulbs may be mounted in special lamp housings from which the light is gage the post I68 and the stud I12 as shown in Fig. 9, the brush carrier 30 is in its neutral position (Fig. 5). However, on turning the brush carrier into the operative position shown in Fig. 10, for instance, the stud I12 thereon rocks the lever I 58 into the dot-and-dash line position I 58a against the tendency of the spring I10 to return said lever into the position shown in Fig. 9. The

force of the spring I10 is such that it will not release the brush carrier in either operative position from locking engagement with the lock disc .I40, but willguickly return the brush carrier to its neutral position once the lock disc is depressed and the brush carrier released for rotation. An-

other post I13, mounted on the cover plate I8 of the switch housing, engages either edge I15 of a cut-out in the end plate 34 of the brush carrier and stops the latter before the same may be turned beyond either operative position to such emitted through arrow-shaped windows, or a flasher may be interposed in the lead I86 and the conventional parking light bulbs and/or the conventional stop light bulbs of thevehicle may be used for giving direction signals in form of periodic light flashes at the left or right side of the vehicle in the manner disclosed in my copending application, Serial No. 298,793, filed October 10, 1939.

The conductor-carrying shaft 98 is so connected with the steering mechanism of the vehicle that the conductor 92 assumes the neutral position shown in Fig. 5 when the vehicle proceeds in a straight direction, but is rotated from its neutral position in a clockwise and counterclockwise direction, respectively, as viewed in Fig. 5 on turning the vehicle from a straight direction of movement to the left or right, respectively, and is returned to neutral position on bringing the vehicle back. into a straight direction of movement. This driving connection, which forms no part of the present invention, may be like the one shown in my copending application, Serial No. 305,638, filed November 22, 1939, in which the rotary conductor of the switch is driven from the ball arm-carrying trunnion shaft in a conventional steering gear housing and the switch itself is advantageously mounted on a bracket which is in turn mounted on said housing. The present switch I2 is mounted on the end cover I8 of theswitch housing.

an extent that the stud II2 would leave the straight end of the engaged lever I58 or I60 and move underneath the lever portion I58!) in Fig. 10, for instance, to jam the switch.

Mounted at I76 in the switch housing I4 is a conductive sleeve I'I8 (Figs. 2 and 5) in which a brush I80 is slidable. Threaded into the sleeve I18 is a terminal post I82 to which may be secured by a nut I84 a lead I86 that connects said post with any suitable source of electrical "energ such as the storage battery I88. Lo-

cated within the sleeve I18 and interposed between the terminal post I82 and the brush I80 is a spring I98 which urges said brush into engagement with the conductor 92.

The otherterminals 84 on the switch housing l4 may be connected through pairs of leads I92, I94 and I96, I98, respectively, with grounded pairs of signal bulbs 200, 202 and 204, 206, respectively. The bulb pairs 200, 202 and 204, 206,

respectively, may be located at the left and right side, respectively, of an automotive vehicle and the bulbs 202 and 206 may, for instance, be at the front of the vehicle, in which case the other bulbs 200 and 204 would be at the rear of the ,may be rocked by a manual actuator which is located on the hub of the steering wheel and mounted at the upper end of an actuator shaft which extends through the hollow steering shaft that carries the steering wheel, all as shown in my copending application, Serial No. 298,794, filed October 10, 1939. The driving connection between the lower end of the actuator shaft and the brush carrier 30 may be like the one shown in my copending application, Serial No. 298,794, filed October 10, 1939.

In the neutral position of the brush carrier, the leaf springs 89 normally arrest the brush-holding sleeves 68 in the position illustrated in Fig. 5 in which the brushes I2 are kept out of engagement with the periphery of the disc 94. Preferably integral with the circular conductive tracks in the switch housing are cams 2I6a. and 2I6b, respectively (Figs. 1 and 5), which are adapted to cooperate with followers 2 I8 of the conductive sleeves 68a and 681), respectively (Fig. 3), to force the latter inwardly on turning the brush carrier from its neutral position into its operative positions, respectively. Thus, on rocking the brush In the operative position shown in Fig. 6, for

to the grounded signal bulb 2M and another lead I98 passes to the grounded signal bulb 206. After thus manuall setting the switch for a right turn signal, for instance, the rotary conductor 92 remains in the neutral position shown in Fig. 6 until the vehicle actually starts to turn toward the right. Thereupon the conductor is turned counterclockwise as shown in Fig. '7 due to its previously explained driving connection with the steering mechanism of the vehicle, with the result that the brush 12 in the sleeve 68a remains in engagement with the conductor 92 and the abovedescribed right-turn signal circuits remain closed even though the brush carrier 38 is released from the lock disc I48 and spring-returned to the neutral position shown in Fig. 7 as soon as the conductor 92 is turned from its neutral position. To assure permanent engagement of the feed brush i88 with the conductor 92 in any angular position of the latter, the driving connection between said conductor and the steering mechanism of the vehicle is preferably such that the former does not travel much beyond the position shown in Fig. '7 when the vehicle negotiates a right turn of th shortest possible radius. soon as the driver of the vehicle, while in the right turn, starts to turn the steering wheel counterclockise in order to bring the vehicle back to a straight direction of movement, the conductor 92 y will be turned clockwise as viewed in Fig. '7 and 3 return to its neutral position when the vehicle again proceeds in a straight direction. Shortly before the vehicle resumes itsstraight direction of movement, the lobe 22911 of a cam 222 on the conductor-carrying disc 94 cooperates with a follower 224a on the conductive sleeve 68a (see also Figs. 3 and 8) and forces the latter outwardly to such an extent that the notch 89b in the sleeve clears the spring apex 88 and the other notch 86a partially, rather than completely, registers with said spring apex when the crest 226 of the cam 222 reaches the follower 224a of the sleeve. The forc of the spring 89 thereupon urges the sleeve 58a further outwardly until the notch 8611 therein is in complete registry with the spring apex 88. This slight additional outward motion of the sleeve GM as caused by the spring 89 takes the former completely out of engagement with the cam 222 so that said sleeve is, in the neutral position of the brush carrier, never even touched by said cam when the rotor 92 is subsequently turned in either direction by the steering mechanism on negotiating a turn or turns without manually setting the switch, The sleeve 88b has a follower 2241) (Fig. 3) for similar cooperation with the lobe 2201) or" the cam 222 when the switch was set for left-turn signals. The earn 222 is in the form of a circular flange on a plate 228 which may be molded into the disc 94 in the manner shown in Fig. 2 or secured to the latter in the manner shown in Fig. 3. The ends of said flange are bent inwardly and form the cam lobes 228a and 2281).

The operation of the switch for closing the left-turn signal circuits through the signal bulbs 200 and 282 is exactly the same as that explained for closing the right turn signal circuits, except that the rotary motions of the brush carrier 30 and the conductor 92 take place in directions opposite to those for closing the right-turn signal circuits, as will be readily understood. It is also evident that no signal circuits will be closed unless the switch is manually set, because in the neutral position of the brush carrier 30 the brushes 12 are out of engagement with the conductor 92 and will engage the latter only when the brush carrier is manually turned to either operative position.

Supposing the switch is manually set for a right-turn signal (Fig. 6) and the vehicle is subsequently turned to the left, it is evident that the conductor 92 will then be turned from its neutral position clockwise as viewed in Fig. 6, with the result that the brush carrier 38 is immediately released from the lock disc I48 and spring-returned to its neutral position. While the brush carrier is thus returned to neutral position, the follower 224a on the brush-holding sleeve 68a meets and cooperates with the advancing lobe 226a of cam 222 and is thereby forced into the retracted position shown in Fig. 5 before the brush carrier arrives in its neutral position. To avoid jamming of the switch in this contingency, th sleeve 68a must evidently be out of cooperative alignment with the cam 216a when the advancing cam lobe 229a forces said sleeve in the spring-returning brush carrier into the retracted position shown in Fig. 5. As this holds also true when the switch is manually set for left turn signals and the vehicle is subsequently turned to the right, both cams 2I6a and 2 I61) on the stationary conductive tracks are in the neutral position of the brush carrier preferably as far angularl removed from the conductive sleeves 68 as is permissible in order that said cams may still perform their previously explained function. Likewise, the lobes 220a and 2281) of the cam 222 are in the neutral position of the conductor-carrying disc 94 preferably as far angularly removed from the cams 2 i 6 as is permissible in order that said cam lobes may still perform their previously explained function. In so coordinating the cams Zita and Zliib with the cam lobes 228a and 220b, a jamming of the switch is practically impossible, particularly since the brush carrier, once released from the lock disc M8, is spring-returned to its neutral position far quicker than the driver of the vehicle can possibly turn the steering wheel for negotiating a turn.

For all intents and purposes, the conductor 82 may be completely annular without in the least interfering with the described operation of the switch. However, if the conductor 92 is only of the angular extent shown in Fig. 5, the present switch may readily be converted into a switch which is not only manually operable but automatically as well, like the switch shown in my prior Patent No. 1,910,869, May 23, 1933. Evidently, on bending the cams 2H3 against the switch housing M and removing the cam 222 from the disc 94, and on depressing both brushho-lding sleeves 68 in the brush carrier 38 so that the spring apexes 88 register with the notches 86b and the brushes I2 ride on the conductor 82 or on the periphery of the disc 94, as the case may be, the left and right turn signal circuits are automatically closed when the vehicle is turned to the left or right, respectively, even though the switch has not previously been manually set.

I claim:

1. In a signal switch, a conductor; two relatively movable members; one member carrying contacts yieldingly urged into engagement with said conductor and automatically locked in a retracted position therefrom regardless of the position of the other member and said other member carrying said conductor; means unlocking said contacts, respectively, on manual movement of only said one member from a neutral position into opposite positions, respectively, relative to the other member in a neutral position; means returning said one member to its neutral position on movement of said other member from its neutral position in either of two opposite directions; and means forcing any conductorengaging contact into its retracted position on return of said one or said other member into its respective neutral position, depending on the direction of the preceding movement of said other member from its neutral position.

2. In a signal switch, a conductor; two relatively movable members, one member being normally yieldingly urged into a neutral position and having contacts yieldingly urged into engagement with said conductor and being automatically locked in a retracted position therefrom regardless of the position of the other member and said other member carrying said conductor; means unlocking said contacts, respectively, on manual movement of only said one member from its neutral position into opposite operative positions, respectively, relative to the other member in a neutral position; means locking said one member in either operative position when the other member is in its neutral position; means causing said locking means to release said one member one movement of the other member from its neutral position in either of two opposite directions; and means forcing any conductor-engaging contact into its retracted position on return of said one or said other member into its respective neutral position, depending on the direction of the preceding movement of said other member from its neutral position.

3. In a signal switch, a circular conductor; two members independently rotatable coaxially of said conductor, one member having spaced contacts yieldingly urged into engagement with said conductor; means locking each contact in a retracted position from the conductor; nonrotatable conductive tracks permanently engaged by said contacts, respectively; first cams causing said locking means to release said contacts, re-

spectively, on manual rotation of said one member from its neutral position in opposite directions into two operative positions, respectively, relative to the other member in a neutral position; and other cams forcing any released contact into its retracted position on rotation of said one or said other member into its respective neutral position, depending on the direction of the preceding rotation of said other member from its neutral position.

4. The combination in a signal switch as set forth in claim 3, wherein said first cams are provided by said tracks, respectively.

5. The combination in a signal switch as set forth in claim 3, wherein said other cams are carried by said other member.

6. The combination in a signal switch as set forth in claim 3, wherein said one member carries an insulated holder for each contact, each contact comprises a conductive sleeve having a stop and a notch and being movable in a holder to and from said conductor, two brushes movable in the sleeve, and a spring in the sleeve urging one brush against said conductor and the other brush into permanent engagement with a track, said locking means comprises a leaf spring on each holder snapping into said notch of the sleeve therein to lock the latter in a retracted position in which its stop holds said one brush out of engagement with said conductor, and said cams cooperate with the sleeves.

7. The combination in a signal switch as set forth in claim 3, wherein said one member carries an insulated holder for each contact, each contact comprises a conductive sleeve having a stop and two notches and being movable in a holder to and from said conductor, two brushes movable in the sleeve, and a spring in the sleeve urging one brush against said conductor and the other brush into permanent engagement with a track, said locking means comprises a leaf spring on each holder snapping into one of said notches of the sleeve therein to lock the latter in a retracted position in which its stop holds said one brush out of engagement with said conductor and snapping into the other notch to hold said sleeve in a position in which said one brush is in engagement with said conductor, and said cams cooperate with the sleeves.

8. The combination in a signal switch as set forth in claim 3, wherein said one member carries an insulated holder for each contact, each contact comprises a conductive sleeve having a stop and a V-shaped notch and being movable in a holder to and from said conductor, two brushes movable in the sleeve, and a spring in the sleeve urging one brush against said conductor and the other brush into permanent engagement with a track, said locking means comprises a leaf spring anchored in each holder and having a V-shaped apex snapping into said notch of the sleeve in the holder to lock said sleeve in a retracted position in which its stop holds said one brush out of engagement with said conductor, and said cams cooperate with the sleeves.

9. In a signal switch, two movable members normally in a neutral relative position; two first contacts carried by one member; a conductor carried by the other member; another contact connectible with either first contact through said conductor, one contact of each connectible contact pair being normally retracted from said conductor and the contact connectible therewith being permanently urged toward said conductor; means causing said one contact of the connectible contact pairs, respectively, to advance into engagement with said conductor on movement of only said one member from its neutral position in opposite directions, respectively; and means causing said advanced contact to return to its retracted position on relative movement between said members into said neutral relative position.

PAUL WEIEN. 

